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I suppose it makes sense in that the windlass can produce short, high amp loads like the starter does and your start battery is better suited to that application than the deep cycle batteries in your house bank.
Why? When you use the windlass the engine should be running... and it is kicking out all the amps the windlass is drawing down... Then, typically, you motor away to raise your main etc. and maybe follow a channel to where you can sail.

Sure you can sail off your anchor and have no need to use the engine. But if you have one... why not? When you do you get some "hot water" as a side benefit.
 

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Aloha 32 & Hunter 26.5
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My marine electrician insists that our windlass should be run off the start battery rather than the house and he has recommended that I rewire it accordingly. I'm dubious about this. As it happens, the house bank (4 Trojan 6v golf cart batteries) is much closer to the windlass than the start battery (AGM CCA 750 90amp). His change will involve extensive recabling plus relocating the windlass breaker. I know this is a much discussed topic. Does anyone have any view about what is preferable?
This is not an easy answer. There are many factors to consider, including existing loads on the house bank, charging systems present, amp draw of the windlass, etc. As a general rule, I tend to like to keep my start battery separate from everything else, so that it can still start the motor & provide charging when everything else is already dead. Your electrician may have a valid reason to override my generality in your specific case. My advice, is to ask him why he thinks that is the best way to go in this particular situation. I'm not a mind reader. I'm not going to second guess his thought process.
 

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I did not get a separate windlass battery and charge and run wiring... I RAN large wires from the house bank where I mounted the windlass switch and there is a large ANL breaker. The battery cable size wires were spendy, but the install was simple. I think the cost of the cables was not more than the "local separate battery approach" Why do I need another battery to worry about. Engine in on when the windlass is used so amps out are being replaced.
And here we see the corners we paint ourselves into with electrical conveniences. What if you absolutely need your windlass and your engine won't start? This is why people should have boats that they can handle without electrical contrivances, and essential gear (windlasses, winches, etc.) need to be as fail-proof and Murphy-resistant as possible. I know lots of people use electrical everything and seem to do just fine but when this stuff lets you down, you'll be against a lee shore with a falling glass. Plan for failure and you won't be disappointed.
 

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This is not an easy answer. There are many factors to consider, including existing loads on the house bank, charging systems present, amp draw of the windlass, etc. As a general rule, I tend to like to keep my start battery separate from everything else, so that it can still start the motor & provide charging when everything else is already dead. Your electrician may have a valid reason to override my generality in your specific case. My advice, is to ask him why he thinks that is the best way to go in this particular situation. I'm not a mind reader. I'm not going to second guess his thought process.
HIs justification is that the windlass places a high load on the battery for which deep cycle batteries are not well suited. According to him it's about extending the life of the house bank. I guess if you have been on the hook for an extended time and the house bank is depleted then that might also result is a voltage drop that was halrmful not only to the windlass but also electrical equipment running off the house. The advantage of the using the start battery (which will be near fully charged) with engine running is that it can be brought back to full charge fairly quickly. I'm not really trying to second guess the expert advice, just wanting to understand the pros & cons and interested in other views -- I'm aware that opinions on this differ.
 

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And here we see the corners we paint ourselves into with electrical conveniences. What if you absolutely need your windlass and your engine won't start? This is why people should have boats that they can handle without electrical contrivances, and essential gear (windlasses, winches, etc.) need to be as fail-proof and Murphy-resistant as possible. I know lots of people use electrical everything and seem to do just fine but when this stuff lets you down, you'll be against a lee shore with a falling glass. Plan for failure and you won't be disappointed.
My 490 ah house bank (2 8Ds house and the optima 55 ah start) can operate the windlass without the engine.
 

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HIs justification is that the windlass places a high load on the battery for which deep cycle batteries are not well suited. According to him it's about extending the life of the house bank. I guess if you have been on the hook for an extended time and the house bank is depleted then that might also result is a voltage drop that was halrmful not only to the windlass but also electrical equipment running off the house. The advantage of the using the start battery (which will be near fully charged) with engine running is that it can be brought back to full charge fairly quickly. I'm not really trying to second guess the expert advice, just wanting to understand the pros & cons and interested in other views -- I'm aware that opinions on this differ.
Deep cycle batteries are designed to provide moderate amounts of current for long periods of time. Start batteries are designed to provide large current for short periods of time. Deep cycle batteries suffer from high current draw. Start batteries suffer from deep discharge.

The number to start with is the current draw of the windlass. The next thing to look at is the size of the house bank. Enough deep cycle batteries in parallel will not cry about a windlass load. The next thing to look at is the reserve capacity of the start battery. Then estimate how long the windlass might need to run, in order to retrieve your full anchor rode. This will require knowing the speed that your particular windlass runs at. They vary. When we have all that info, we can then start to do some math. For reference, the smallest trolling motor that I ever owned would draw 30 amps at max speed pushing an 8' inflatable. I ran that off of a group 24 deep cycle battery. I was able to get more than half an hour of constant run time. Trolling motors that size & nearly double it's size are most commonly run on single group 24 & 27 batteries.

The devil is in the details. Depending on the ratings of the different batteries, the run time of the windlass, the current draw of the windlass, the types of charging equipment you have, and how often you pull up the anchor, some systems may favor using the house bank & others may favor using the start battery. Your existing use of the house bank matters too. If you are already marginal on capacity there, then that can be a major consideration. If you have a 100amp alternator & the windlass only draws 50 amps, that would also be taken into consideration.

I don't see a one size fits all answer here. There are pros & cons to either choice.
 

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My Jeanneau came from the factory with the windlass wired to the engine battery, and interlocked with the engine run circuit so the engine must be running in order to use it. (I think you can use it without the engine running by just having the switch on, if you don't mind listening to the oil pressure alarm the whole time!)

The explanation I got was that the interlock was a response to some serious injuries resulting from children playing with the windlass while the boat was at anchor. Many boats like mine are built for the charter market where such incidents are more likely to happen.

The question of whether to run the windlass on the engine battery or the house bank is one I am grappling with. The idea that cranking batteries are more suited to the motor loads makes sense, but at the same time, if a house bank can handle an inverter drawing 200a then surely it can handle the much smaller windlass draw!

At this point I have left my windlass wired as Jeanneau wired it but upgraded my engine battery. Even with the upgraded battery I still sometimes get a low voltage alarm from my panel when pulling the anchor from the deep!

Sent from my SM-G981W using Tapatalk
 

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My 490 ah house bank (2 8Ds house and the optima 55 ah start) can operate the windlass without the engine
I had a 45' crane that would run all day on 2 8D's. Hoisting and extending significant loads. I doubt very seriously that a windlass would tax those batteries as much as a crane would. The one caveat however is that the batteries never lasted more than 2 or 3 years. They would charge overnight every night during the work week and didn't get a lot of love. Like everything else it's pick your poison. If your house bank were 2 group 31 deep cycle and your start battery a group 27 then I would go with the start battery to operate the windlass for reasons discussed but a 2 8D house bank ......
no worries.
 

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Farewell and adieu to you dear Spanish ladies.
Farewell and adieu you ladies of Spain.
For I’ve bought a gadget that never shall fail me,
And so never more shall you see me again.
 

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Discussion Starter · #31 ·
Thanks so much for all the replies. At this point, it is my new boat. All we have done is stretch out the chain on dock to figure out the previous owners marking lengths. without any load we powered in about 10 seconds at a time without issue. I have no reason to believe there is any issue with a mismatch of gypsy and chain size. I think a lot of what I was told by the PO is his insecurities and cautions for which they may have some basis in truth. I look forward to using the windlass this summer when the water is warm enough to swim, especially once I get the batter in the remote fob replaced.
 
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